Her weight is between the 10-5th percentile and her height is between the 95-90th percentile for her age. She may appear thinner then she is due to her height. She is still in the growth chart which is good; however, you stated she has decreased in weight. If she is vomiting then she needs to be medically checked to determine why. She may need her infant formula changed. She can have regular finger food at this age, which will give her additional food. If you are concerned about her nutrition status, suggest having blood work done too.